1. Field of the Invention.
The invention, in general, relates to a novel rotary cutting blade and, more particularly, to a rotary cutting blade provided with a cutting edge of varying thickness.
2. The Prior Art.
Rotary cutting blades of disk-like configuration are known, for instance, from European patent specification EP 0,709,170 A1 and are used for cutting or slicing food products such as, for instance, cheese, sausage, ham and the like. Such blades operate at high cutting frequencies in excess of 1,000 slices per minute. In industrial production processes, the slices are assembled and packaged in stacks. At the retail level, the slices are then usually spread out in imaginative or fanned-out patterns to be presented for sale in a set-up appealing to purchasers.
In addition to rotationally symmetric circular blades, blades with a sickle-shaped or spiral outer contour have found increasing acceptance. Such blades are provided with a cut-out which forms an angular void or gap in their circumference and which serves incrementally to advance the material being cut, slice by slice, once every revolution of the blade. Such rotational blades, sometimes referred to as slicer blades, yield substantially higher cutting rates in view of the fact that unlike circular blades they require no reciprocal movements normal to their axis of rotation, out of and into their operating position following each cut in order to advance the material into the cutting plane.
Compared to circular rotary cutting blades, the cutting rate of food products is significantly increased by rotary blades provided with a peripheral angular cut-out. Depending upon the kind of material to be sliced and its consistency, the number of rotations of, and, hence, cuts by, such “notched” blades may be as high as 1,500 per minute. The continuous feeding of the material to be cut in a direction parallel to the axis of rotation of the blade leads to higher pressure and, therefore, friction between the blade and the material. This may lead to frictional losses and detrimentally affect the surface of the slices cut. Because of the heat generated by the friction, the visual appearance and taste of the cut slices may suffer as well.
Stepped angular formations in the rotary blade surface, and, more particularly, ground-out voids in their surface facing the material to be cut, are intended substantially to avoid those disadvantages in accordance with the above-mentioned European patent specification EP 0,709,170 A1 and German patent specification DE 196 46 656 C2. For this purpose and for reducing the area of contact between the blade and the material to be cut as well as to reduce vibrations in the blade, the rotary cutting blades are provided in their surface facing the material to be cut with a relatively small annular zone and, also in the surface facing the material, a recessed area radially disposed further inward.
A rotary blade of a similar kind is disclosed by German patent specification DE 101 08 018 A1 in which the cutting edge is shaped as undulations with regularly spaced recesses and elevations to provide for an interrupted cutting sequence when used as intended. Cutting machines equipped with such blades are intended to be more economical. The disadvantage inherent in prior art blades is that, when used, material to be cut will often be trapped in the cutting edge recesses which detrimentally affects the quality and appearance of the cuts and, more particularly, of the cut slices.